The present invention relates to a transconductance amplifier and particularly to a transconductance amplifier with transconductance-adjustable elements.
A transconductance amplifier is an electronic stage which provides an output current in response to a voltage input. Ideally the output current is linearly proportional to the voltage input. The proportionality constant is known as the transconductance gain. Since the voltage output is the product of the output impedance and the output current, the voltage gain is the product of the transconductance gain multiplied by the output impedance.
In differential signal processing applications, mismatch of discrete components or elements of signal processing circuit may have an impact of the performance of the signal processing circuit. For a differential transconductance amplifier, for example, any mismatch may lead to a decrease in impedance and hence reduced gain. It is therefore desirable to reduce any mismatch to maximize the differential gain.